Many computer operating systems are extensible, allowing additional applications to be installed to extend the functionality provided by the computer through the operating system. While such extensibility can make additional functionality available to users, it is not without its problems. Different applications can install and uninstall extensions on computers in different ways, resulting in the additions and removals of extensions that are performed in inconsistent manners. Furthermore, when applications are uninstalled, the different ways in which extensions can be removed can result in the computer operating system being left in inconsistent states. These different manners in which extensions can be added and removed can thus result in inconsistent computer operating system states and provide inconsistent user experiences, which degrade the user experience with the computer.